When interventional catheter devices are inserted into the vascular system, the physician usually starts with a needle stick, followed by dilating the artery in order to insert an introducer sheath device that is left in place for the duration of the procedure. This introducer sheath acts as the main conduit for entry of subsequent therapeutic or diagnostic devices.
In most instances, these introducer sheaths contain a hemostatic component that restricts back-flow of blood from the artery. These hemostasis seals are generally passive and provide sealing around the catheter devices and guide wires that are used during the procedure. In some cases, hemostasis seals can include a septum structure or seal, though which a device such as a guide wire or other medical device component is inserted in order to pass through the hemostasis seal.